Accident investigators expect details recorded in the black box of a Tesla involved in a double fatality earlier this month on Laguna Canyon Road will tell them if the driver was racing.

A search warrant will be required to extract information from the event data recorder known as a black box from the Tesla, which has not been released to the owner, Laguna Beach police Capt. Jason Kravetz said this week. Representatives of the auto maker will assist in the retrieval, he said.

Black boxes, like those used to reconstruct events that precede aircraft collisions, are installed on many vehicles by manufacturers as a way of shielding themselves from liability, according to Byron Block, an auto safety expert in Potomac, Md.

Crash data retrieval systems made by Santa Barbara’s Bosch Diagnostics are installed in most of the major domestic and foreign makes, but Tesla isn’t among them.

“Only the manufacturer can interrogate the black box,” explained Block.

Manufacturers access the data with proprietary tools, writes William Rosenbluth, a collision investigator in Reston, Va., in Forensic Magazine.

Black boxes lack uniformity because automakers want to extract data for their own use; it isn’t available to the car owner or the public, Block said.

Police, though, can obtain the forensic evidence with a search warrant, Kravetz said.

Boxes made by Bosch, which provides sample recovery reports on its website, capture a range of data points for five seconds prior to the impact of two collisions. Among the variables recorded are the vehicle’s speed, acceleration, engine RPM, the impact pulse, seat belt use, air bag deployment, throttle position, rollovers, brakes, ignition cycles and passengers.

Tesla’s are equipped with crash sensors, according to specifications listed on the automaker’s website. But no further detail about what its black box records during the driving experience was noted. Tesla officials did not return phone calls.

Police say the driver of the Tesla, believed to be Laguna Beach physician Robert Pettis, crossed into oncoming traffic in the early morning hours of April 2, plowing head-on into a 1990 Honda headed inbound near El Toro Road. Driver Alberto Casique-Salinas and passenger Armando Garcia Gonzales died at the scene. Both men worked for Laguna Beach’s Stewart’s Landscaping.

“When you have such an impact, there has to be enormous speed,” said Los Angeles attorney Tigran Martinian, hired by Salinas’ family. The Tesla’s weight, twice that of the Honda, isn’t enough to account for the damage, he said.

Mechanical engineers and accident reconstruction specialists will determine the speed of the vehicles, said Martinian, who also sent experts to the scene.

Police say they have questioned the driver of the Tesla as well as the driver of a white Mercedes, who has not been identified. The Tesla’s driver told police dispatchers he had been cut off by a Mercedes. No one has yet been charged and the investigation is not expected to conclude for several weeks, Kravetz said.

Residents continue to debate whether racing played a role in the collision. Tesla’s Model S, for instance, can dash from zero to 60 m.p.h. in 4.4 seconds, according to a September review in the New York Times.

Meanwhile, more than $9,100 has so far been contributed to a fund on behalf of the victims’ families. Salinas is survived by his wife, three teenage children and an adult son, his mother, a brother and a sister, Martinian said. “They were all dependent on him,” he said. Services for both men were held last week in Santa Ana.

Police Employee Association President Larry Bammer intends to finalize the collection by April 30.